Boiler



y 1939- J. M. SHI MER 2,156,610

I BOILER Filed Nov. 16, 1936 4 Sheets-Sheet l 4 INVENTOR Q ATTO I? NEY'S y 2, 1939- J. M. SHIMER 2,156,610

BOILER 'Fi led Nov. 16, 1936 4 Sheets-Sheet 2 INVENTOR 24 QfOH/VMJH/ME/P.

ATTO RN EYS BOILER Filed Nov. 16, 1936. 4 Sheets-Sheet s INVENTOR Jo H/VMSH/MER. BY

ATTO R N EYS Patented May 2, 1939 PATENT Torrie];

BOILER John M. Shimer, Dallas, Tex., assignor to Oil Well SupplyCompany, Dallas, Tex., a corporation of New Jersey Application November16, 1936, Serial No. 111,149

Claims.

My invention relates to a fire tube boiler of the locomotive type,particularly to a boiler for use in the drilling of petroleum wells andother uses where a portable boiler is required or one that may be movedfrom one location to another.

Boilers heretofore used in oil field Work have been of the locomotivetype without insulation against loss of heat. Consequently the loss ofheat by radiation is high, increasing with the area of boiler wall. Alength is reached at which the amount of heat absorbed by the boilerwater from the combustion gases does not very greatly exceed that lostby radiation from the boiler surface required to recover this heat. Theboilers have therefore been generally arranged to provide an exhaust gastemperature of about 750 F. in normal operation.

In my invention a more efficient use of the heat of the boiler fluegases is obtained by providing shorter length of boiler so that asmaller heat radiating boiler surface is provided and in using thehigher temperatures of the flue gases resulting from this shortening insuperheating' steam from the boiler. For example, instead of having anexhaust flue gas. temperature of 750, the temperatures from the firetubes of the boiler in my invention may be from 1000 to 1200 F. and theheat of these hotter gases is then absorbed in superheater tubessupplied with steam' from the boiler and with which the hot flue gasesare brought into contact before passing to the exhaust stack. Inasmuchas the use of steam is generally variable and to avoid overheating thesuperheater tubes at times of low steam consmnption, by-pass exhaustsare provided for the flue gases-so arranged that when the temperature.of the superheated steam rises beyond certain limits the flue gases arelay-passed direct to the exhaust stack or partly by-passed instead ofthrough thesuperheater. This arrangement also tends to insure a supplyof superheated steam at approximately constant temperature. Forconvenience in cleaning the fire tubes of the boiler the superheater ismade detachable so that it may beremoved from the smoke box of theboiler as a unit giving free access to the ends of the fire tubes. Acover may be bolted to the end of the smoke box on removal of thesuperheater unit so that the boiler may be used independently.

The various features of the invention are illustrated by way of examplein the accompanying drawings, in which- Fig. 1 isa plan View: Fig. 2avertical longitudinal section of a fire'tube boiler embodying thepreferred form of the invention; Fig. 3 is an end view of the boilersuperheater taken from the superheater end of the boiler; Fig. 4 is avertical section on a line 4-4 of Fig. 2; and Fig. 5 is a detail viewpartly in section of the tempera- 5 ture control mechanism.

In the accompanying drawings the invention is shown as applied to aboiler l0 having the usual fire box II and steam and water cylinder l2through which the fire tubes 13 extend to connect the combustion chamberl l with a smoke box M. This smoke box I4 is provided with an exhaustflue l5 having a control damper l6 and.

connected to a stack l1.

The front end of the smoke box M opens into an extension or superheaterchamber l 8 in which are banks of steam pipes I9 supplied with steamfrom the boiler l0 through a takeoff pipe 29 and a branch pipe ii thatleads to a manifold 22 at the upper end of the bank of tubes IS. Thesteam passing through the banks of tubes i9 is received in a lowermanifold 23 at the bottom of the bank of tubes and withdrawn through asupply pipe 24. The superheater chamber I8 is closed by a baffle 25 tothe smoke box M from its upper end to about the middle level of thesmoke box thus causing the gasesto pass from the smoke box into thelower part of the superheater chamber I8. A horizontal bafile 26 extendsfrom the lower edge of the baflle 25 to 'a distance short of 'the frontend of the superheater chamber to cause the gases to flow forwardly inthe lower half of the superheater chamber, thence to pass upwardly infront of the front edge of the baille 2E3 into the upper part of thesuperheater chamber as indicated by the solid line arrows. An exhaustflue 21 extending upwardly from the rearmost part of the superheaterchamber draws the gases 'backwardly above the baffle 26 from whence theypass into the stack IT to which the flue 21 is connected. The flue 2'!is provided-with a' damper 28 which is mounted on a shaft 29 coaxiallywith the shaft of thedamper 16. The plane of the damper 28 isv at aright angle or at from the 7 understood that various other shapes andsizes of superheater chambers may be employed. For convenience inremoving the superheater chamber, it is mounted on a frameworkcomprising a pair of skids 3| so that upon detachment from the smoke boxit may be slid sidewise or at right angles to boiler.

The dampers l6 and 28 are thermostatically controlled so that the damperi6 will open more widely and the damper 28 be moved toward closedposition when the temperature of the superheater steam passing throughthe pipe 24 increases beyond that for which the apparatus is set. Forthis purpose a thermally expansible fluid container of any suitable typein the steam pipe 24 is connected by means of a tube 32 to a cylinder 33where it moves a piston stem 34 downwardly against the tension of aspring 35. The lower end of the piston rod 34 is adjustable andpivotally connected to a horizontal lever 36 at a point between the endsof the lever. One end of the lever 36 is pivotally connected to a valvestem Bl which extends into a valve cylinder 38 and is attached thereinto a sliding piston valve 39. Steam is supplied from the pipe 24 orother source to a tube 4|! to the valve cylinder 38 at a point between apair of outlet tubes4l and 42. The valve 39 in its normal positioncloses both the ports to the tubes 4| and 42 from the steam admittedthrough the tube 40. When moved upwardly from its position it puts thetube 4| in communication with the supply pipe 4|! and steam then passesthrough pipe 4| to the lower end of a valve actuating cylinder 43 to thepart to which the pipe 4| is connected. When the valve 39 is loweredfrom its position communication between the supply pipe 40 and theoutlet pipe 4| is maintained closed but communication is open to thepipe 42 so that steam flows from the supply pipe 40 through the pipe 42to the upper part of the cylinder 43 to which the pipe 42 is connected.

A piston 44 is positioned in a cylinder 43 between the ports of thepipes 4| and 42 therein so that when steam is admitted by the pipe 4| tothe lower part of the cylinder 43 it forces the piston 44 upwardly andwhen steam is admitted through the pipe 42 to the upper part of thecylinder 43 it forces the piston 44 downwardly. With the upward movementof the piston 44 the steam displaced may pass through the pipe 42 andvent below the valve 39 to the atmosphere through a suitable vent 43' inthe valve chamber 38 and similarly when the piston 44 is moved downwardthe exhaust steam is exhausted through pipe 4| and above the valve 39through vent 44 to the atmosphere.

It will therefore be apparent that with an increase in temperature ofthe steam in the pipe 24 the expansible fluid would pass through thepipe 32 to the upper end of the cylinder 33 and will displace the pistonrod 34 downwardly against the action of the spring'35 thus movingdownwardly the lever 36 and the valve stem 37 to open a passage throughthe valve chamber 38 from the pipe 4|! to the pipe 4| and to exhauststeam through the pipe 42. Thus steam will be admitted to the lower partof the cylinder 43 to force the piston 44 upwardly. When the exp ansiblefluid contracts with a drop in temperature of the steam passing throughthe pipe 24 the spring 35 will lift the piston rod 34, lever 3'6, valvestem 31 and valve 39 to admit steam from the pipe 49 and through thepipe 42 to the upper part of the cylinder 43 and to exhaust it throughthe pipe 4| from the lower part. It will therefore be apparent that thepiston 44 rises with an increased temperature of steam in the pipe 24and falls with the falling temperature.

The movements of the piston 44 are transmitted to the dampers i6 and 28by means of a piston rod 45 extended upwardly through a suitablestuffing box 46 in the cylinder 43 and connected through the link 41,lever 48, rotatable about pivot 48, adjustable link 49 and crank armwith the shaft 29 with which the dampers l6 and 28 are rotated. Thus,when the piston 44 rises with an increase in temperature, it swings thedampers clockwise as shown in Fig. 3 thereby closing the damper 28 andopening the damper I6 causing less of the fire tube gases to pass intothe super-heater and more of them to by-pass through the flue I5directly into the stack l'l. Conversely when the temperature ofsuperheated steam drops the piston 44 also is lowered, rotating thedampers 28 and I6 counter-clockwise so that 28 rotates toward openposition and Hi towards closed position to increase the amount of hotgases passing'through the superheater and a decreased quantity by-passedthrough the flue l5.

It will be noted that the lever 36 is pivoted at one end to the pistonrod 45 and at the other to the valve stem. 37. When the expansibleliquid of the thermostatic element forces the piston rod or stem 34downwardly, the lever 3'8 pivots on its connection to the piston rod 45thereby pushing downwardly the valve stem 3? and opening the passage 42for the supply of fluid to the upper side of the piston 44. This causesa lowering of the piston rod 45 whereupon the lever 36 pivots about itsconnection to the thermostatic piston rod 34 lifting the valve stem 3'!until the passage to the tube 42 is closed. Therefore with each positionof the thermostatic element piston 34 steam will be supplied eitherthrough the pipe 4| or the pipe 42 until the piston 44 and piston rod 45take a corresponding position. From this it will be apparent that witheach temperature of the steam in the pipe 24 the thermostatic elementwill move the dampers l6 and 28 through the lever 36 to a definiteposition. For example,

a higher temperature will tilt the dampers l6 and 28 to by-pass more ofthe exhaust gases through the exhaust l5 and less throughthesuperheater, whereas a drop to a lower temperature will set the dampersto a definite position supplying a larger proportion of the hot gasesthrough the superheater and a lesser proportion through the flue i5.

Through this controlled apparatus therefore the temperature of thesuperheated steam supplied through the pipe 24 is kept within fixedlimits and excessive temperatures that might burn out or injure thetubes is of the superheater are avoided. In the event that thesuperheater should be injured or placed out of commission, it may bedisconnected from the pipe 20 by a valve 5| in the pipe 2| and theofftake pipe 24 may be closed by a valve 52. Steam may then beb-y-passed to the pipe 24 directly from the oiTtake pipe 28 through aby-pass pipe 53 connected between the pipes 20 and 24 and normallyclosed by a valve 54. 'The boiler may be provided with the usual dialthermometer 55. When the superheater is to be disconnected from thesmoke box of the boiler its steam connections with the connecting pipe2| may be disconnected at the flanged union 55 and its connection to thesupply pipe 24 may be opened at the flanged union 51.

Through the above invention therefore I have provided a boiler in whichthe heat of the combustion gases is more effectively employed since itis used to superheat steam rather than for the generation of steam forwhich a larger surface exposed to the atmosphere would be required. Alsothe superheater being readily detachable leaves the front ends of thefire tubes readily accessible for cleaning. The danger inherent inboilers of this type in which the demand for steam varies Widely andirregularly of burning of the superheater tubes at times of low steamconsumption is avoided.

What I claim is:

1. A locomotive type fire tube boiler having a smoke box, a superheaterchamber extending forwardly from said smoke box and communicatingtherewith, superheater tubes in said chamber, a baflle in saidsuperheater chamber so constructed and arranged as to cause gases fromsaid smoke box to pass forwardly to the lower part of said superheaterchamber thence upwardly and rearwardly, exhaust flues one for said smokebox and one for said superheater chamber and thermostatically operateddampers in said flues to control the alternative passages of exhaustgases through one or the other of said flues.

2. A locomotive type fire tube boiler having a smoke box, a superheaterchamber extending from said smoke box, superheater tubes in saidsuperheater chamber, exhaust flues and dampers therein from said smokebox and said superheater chamber respectively, means controlledthermostaticallyby steam from said superheater tubes to position thesaid dampers to definite positions for each temperature of said steam,said means comprising a steam cylinder and piston, a valve forcontrolling the admission of steam to opposite sides of said cylinderand piston, a valve having a valve stem, a lever pivoted between saidvalve stem and said piston and a thermostatically actuated rod pivotallyconnected to said lever between said valve stem and said piston.

3. A boiler comprising a fire box, a smoke box, a steam and watercylinder between the fixe box and the smoke box, said cylindercontaining a plurality of fire tubes to conduct gases of combustion fromthe fire box to sad smoke box, a superheater chamber forwardly of thesaid smoke box, bafile means to direct gases of combustion from thesmoke box into the lower portion of said superheater chamber thenforwardly and rearwardly therein, a smoke stack, conduit means toconduct gases of combustion from the smoke box to said stack, conduitmeans to conduct gases of combustion from the superheater chamber tosaid stack, means to pass steam from said steam and water cylinderthrough said superheater chamber countercurrent to the passage of gasesof combustion therethrough, and damper means in each said conduit toregulate the amount of said gases passing through said superheaterchamber into said stack.

4. The combination of claim 3, the length of said steam and watercylinder being such as to provide in said smoke box a gas temperature atleast sufiicient to superheat the steam in said superheater chamber.

5. The combination of claim 3, in which means actuated by thetemperature of the superheated steam is provided to regulate the saiddamper means to obtain a substantially constant superheated steamtemperature under varying load conditions.

JOHN M. SHIMER.

